Taxonomy and Classification Notes
Taxonomy and Binomial Nomenclature
- Taxonomy:
- The science of classifying organisms based on relationships and common structures.
- Binomial Nomenclature:
- A two-name system for all living things.
Why Classify Living Things?
- An estimated 8.8 million different species exist, but only 1.9 million have been described.
- Classification helps organize organisms according to similarities.
- Understanding biological diversity is crucial before studying population evolution.
- Two Kinds of Biological Diversity:
- Species diversity: the number of different species.
- Genetic diversity: the variation in inherited traits within a species.
Carl Linnaeus and Taxonomy
- Carl Linnaeus developed a two-naming system based on physical and structural features of organisms.
- Published in "Species Plantarum" (1753).
- The more features organisms share, the closer their relationship.
Linnaeus's Order of Classification
- Hierarchical structure:
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
- Mnemonic: Kids Play Catch Over Farmer Green's Stables
Binomial Nomenclature Details
- Linnaeus established rules for naming plants and animals using a two-word system (Latin words).
- Scientific names are based on characteristics like color or habitat.
- Example: Castor canadensis
- Castor means beaver.
- canadensis means from Canada.
Scientific Name Rules
- First word = Genus:
- Second word = species:
- Not capitalized.
- Never stands alone (needs the Genus).
- Both Genus and species words are either Underlined or Italicized.
- Examples:
- Felis domesticus or Canus familiarius
- Felis leo, Felis concolor; Canus latrans, Canus lupus
Scientific Names: Relationships
- Scientific names indicate if two organisms are closely related.
- North American black bear: Ursus americanus
- Grizzly Bear: Ursus horribilis
- Polar Bear: Ursus maritimus
- All belong to the same genus (Ursus) indicating a close relationship.
Species Relationships
- Bears (Family - Ursidae) belong to the order Carnivora.
- Closest relatives in the same order:
- Family - Canidae (dog family)
- Family - Mustelidae (weasel family)
- Family - Procyonidae (raccoon family)
- Family - Phocidae (true seal family)
- Family - Otariidae (eared seal family).
- Seals & sealions are believed to be the closest relatives of bears.
Examples of Classification
- Specific examples of common names, scientific names, and family:
- Red squirrel (Tamiasciurus hudsonicus, Sciuridae)
- Shorttail weasel (Mustela erminea, Mustelidae)
- Groundhog (Marmota monax, Sciuridae)
- Mink (Mustela vison, Mustelidae)
- Eastern chipmunk (Tamias striatus, Sciuridae)
- River otter (Lutra canadensis, Mustelidae)
- Fisher (Martes pennanti, Mustelidae)
- Muskrat (Ondatra zibethica, Cricetidae)
- Black-footed ferret (Mustela nigripes, Mustelidae)
The Six Kingdoms
- Linnaeus proposed a 2 Kingdom System:
- Kingdom Plantae & Kingdom Animalia
- Later discovery of single-celled organisms led to:
- Recognition that some single-celled organisms lacked a true nucleus:
- Monera subdivided into:
- Kingdom Archaebacteria
- Bacteria in harsh environments (hot springs, salty & acidic).
- Kingdom Eubacteria
- Possess a rigid cell wall.
Approaches to Classifying Organisms
- Two-kingdom system (Linnaeus - 1735):
- Five-kingdom system (Whittaker - 1969):
- Monera, Protista, Fungi, Plantae, Animalia
- Six-kingdom system (Woese - 1977):
- Eubacteria, Archaebacteria, Protista, Fungi, Plantae, Animalia
- Three-domain system (Woese - 1990):
- Bacteria, Archaea, Eukarya
Kingdoms and Associated Groups
- Illustrative examples of organisms within each kingdom.
- Kingdom Plantae:
- angiosperms, pteridophyta, gymnosperms, tracheophytes, bryophyta, rhodophyta, phaeophyta, chlorophyta
- Kingdom Animalia:
- echinodermata, annelida, arthropoda, mollusca, chordata, nematoda, cnidaria, rotifera, platyhelminthes, porifera
- Kingdom Fungi:
- basidiomycetes, ascomycetes, zygomycetes, gymnomycota
- Kingdom Protista:
- chrysophyta, sarcodina, pyrrophyta, ciliophora, sporozoa, mastigophora
- Kingdom Eubacteria:
- Kingdom Archaebacteria:
- extreme halophiles, methanogens, extreme thermophiles
Phylogeny
- Phylogeny: The history of the evolution of organisms.
- Phylogenetic tree:
- Starts from the most ancestral form.
- Includes branching of all its descendants.
Classification Examples
- Classification breakdown from species to order:
- Felis catus (domestic cat)
- Genus: Felis
- Family: Felidae
- Order: Carnivora (Feloidea)
- Mephitis mephitis (striped skunk)
- Genus: Mephitis
- Family: Mustelidae
- Order: Carnivora (Canoidea)
- Lutra lutra (European otter)
- Genus: Lutra
- Family: Mustelidae
- Order: Carnivora(Canoidea)
- Canis familiaris (domestic dog)
- Canis lupus (wolf)
- Genus: Canis
- Family: Canidae
- Order: Carnivora (Canoidea)
Dichotomous Key
- Dichotomous Key:
- Used to help identify an organism.
- Involves a series of choices that lead to further choices.
- Continues until the organism can be identified.
- Activity: Dichotomous key activity to identify creatures (complete first 5).
- Tomorrow: Activity on Insects
Kingdom of Pasta – Naming Game
- Sort individuals into THREE related groups.
- These 3 groups may be members of the same Genus.
- Give the individual pastas a scientific name (Genus species).
- Try to make the names descriptive & Latin sounding. (USE GOOGLE TRANSLATE English – Latin)
- Genus species names are always italicized.
- Genus is CAPITALIZED & species name is lower case.
- For each of the 3 groups describe the commonalities each pasta shares.
- Submit your names & classification descriptions by table.